They make the point in this episode that every time the Defiant sends out one of its sensor pulses, it will give away its own position. The solution is to change speed and course each time a pulse is sent out. Unfortunately, we see plenty of shots of the ship sending out multiple pulses whilst staying on the exact same course at the same speed, or even staying completely stationary.

Great Moment :

Okay, so the whole episode is an excuse to do a submarine episode in Star Trek. Well, I like submarine movies, so to me that's a good thing.

Plotline

When the Defiant attends a secret meeting with the Karemma, the Jem'Hadar launch an attack which ends with both sides hiding in the atmosphere of a gas giant. Badly damaged, Worf must command the ship while the Jem'Hadar continue their persuit. Meanwhile, Quark and a Karemman representative have a little heart to heart over an unexploded enemy warhead.